1. Field of the Invention
Embodiments of the invention relates to 3D display technical field, more particularly, relates to a liquid crystal lens and a 3D display device having the same.
2. Description of the Related Art
In everyday life, people use two eyes to view external objects having senses of three-dimensional space around their surroundings. In three-dimensional (3D) display technology, people obtain three-dimensional space sense using binocular stereo vision principle, the main principle of which is to allow left and right eyes of a viewer to receive different images respectively, and the images received by the left and right eyes are analyzed and combined by brain, thereby making the viewer generate three-dimension feeling.
Currently, 3D display technology comprises naked eye type and glass type. The so-called naked eye technology is that 3D video images which have been encoded are transmitted to the left and right eyes separately by performing special processes on a display panel, so as to allow the viewer to experience three-dimensional feeling via naked eye without stereoscopic glasses.
Recently, in a display device for achieving naked eye display, a shield such as a grating (raster) barrier, a liquid crystal lens or the like is provided in front of a light source array of a liquid crystal display (LCD). A plurality of visual areas are formed at front side of the display panel using the grating barrier or the liquid crystal lens, so that light emitted from different sub-pixel units on the display panel is impinged on different visual fields. Therefore, eyes of the viewer may focus on the different visual fields, thereby generating 3D feeling.
The principle of the liquid crystal lens is that light beam is converged or scattered based on birefringence characteristic of liquid crystal molecules and arrangement orientation thereof varied with distribution of electric field, so that optical focus of the light beam can be changed in a small space by controlling arrangement orientations of the liquid crystal molecules by changing voltage. However, since the liquid crystal molecules themselves used in the liquid crystal lens have optical anisotropic characteristic, the light directed onto the liquid crystal lens is required to be polarized light. Thus, the light emitted from the display must be the polarized light to achieve the naked eye 3D display. For a non-polarized light display, such as an organic electroluminescent display (OLED), a plasma display panel (PDP) and a cathode ray tube (CRT) display, it is necessary to dispose a layer of polarizer between the display and the light barrier to change the emitted non-polarized light into the polarized light and then achieve 3D display effect by the liquid crystal lens. During such process, the light emitted from the display may be lost, thereby affecting transmittance of the 3D display device. Further, display brightness will be reduced by 50% or more, which may result in deterioration of the 3D display effect.